集光伏准并网的混合电池储能拓扑优化及其稳定运行理论研究

The battery energy storage system is an important technical foundation for the smart grid construction, renewable energy connected to the grid,and large-scale development of electric vehicles. The project mainly studies on power conversion systems (PCS) of hybrid battery storage with photovoltaic generation,mutual coupling mechanism of interface circuits and its inhibition method.A multi-port integrated DC/DC conver-ter containing photovoltaic generation and battery energy storage will be explored to increase conversion efficiency of photovoltaic power and system power density.The integrated converters are cascaded, which ensures that the battery equalization charge and discharge,and avoids the whole battery group capacity decline or failure due to individual differences in the parameters of them. Simultaneously, the hot spot effect of photovoltaic solar can be weakened.The DC bus supporting technology without the link electrolytic capacitor is studied to further improve the lifetime and reliability of the system. From frequency domain and time domain, the mechanism of mutual coupling effect and suppression method of multi-type power conversion units are researched, to ensure the stable operation of the system.The expected results will lay theor- etical and experimental basis for the efficient using of renewable energy such as photovoltaic cells and high-power energy storage systems.

电池储能系统是支撑智能电网建设、可再生能源接入电网、大规模电动汽车发展的重要技术基础，本项目针对含光伏电源的多种电池混合储能功率变换系统（PCS）及其接口电路的相互耦合机理与抑制方法开展研究，探索具有光伏发电和电池储能的多端口集成直流-直流变换器，以提高光伏电源的转换效率和系统的功率密度。研究具有自动均衡充放电同时又可以避免光伏热斑效应的集成变换器级联结构，以解决由于个体电池参数差异，导致储能电池组整体容量下降或失效，和由于热斑效应而影响光伏电池整体发电效率降低的问题。探索减少电解电容的直流母线支撑技术，以进一步提高系统的使用寿命和可靠性。以此为基础，从频域和时域全面探索多类型电能转换单元相互耦合影响的机理及其抑制方法，确保系统的稳定运行。预期成果将为光伏等低压可再生微源的高效利用，为大功率储能系统的发展奠定理论和实验基础。

电池储能技术的应用领域十分广泛，包括光伏等可再生能源发电、大规模电动汽车发展、未来智能电网和虚拟电站的建设等。单独光伏并网发电相当于把光伏能量先存储在大电网中，再分配给相关负载，这对储能性负载（如电动汽车、各类电池驱动移动设备等）而言相当于增加了能量流动的路径，势必降低光伏能源的利用率。另外，大规模的直接光伏并网发电将给现有电网造成极大的冲击，甚至影响电力系统的稳定性。本项目针对光伏发电和储能应用领域，开展了两级式高效率高可靠性混合电池储能功率变换系统架构，根据系统所需多种功率变换器的特点，从性能，成本和易于模块化等多个目标出发，深入探究了多种功率变换电路结构的内在规律及形成机理；建立了减少电解电容的直流母线电压支撑技术；研究了适于光伏发电和储能的高增益、低输入电流纹波、低电压应力的单向DC/DC变换器和双向DC/DC变换器，又研究了智能模糊最大功率跟踪技术；探索了不同功率流动路径时各变换器之间的交互作用和稳定性；研制了50kW的混合电池储能功率变换系统实验平台。本项目研究成果为光伏发电和储能提供了新思路，为智能电网的发展奠定了理论和技术基础。